esdir is a very small object inspection tool like dir() in Python. It is wrapper over Object.getOwnPropertyNames() ES5 API, and shows what properties are available for the object you passed.

var dir = require('esdir');

dir(''); // => [ 'length', 'constructor', 'valueOf', 'toString', 'charAt', ...]
dir(function(){}); // => [ 'length', 'name', 'arguments', ... ]
dir(10); // => [ 'toFixed', 'toExponential', 'toPrecision', ... ]

This project is built with Babel. If you want to use ES2015 source, require/import like require('esdir/src').